"There's an invidious fiction underlying most market reports," Salmon writes. Specifically, it's that the markets' every gyration has a cause, and that a dispassionate observer can divine that cause by looking at the numbers and asking the right questions. Sometimes, pointing out there might not be a reason is "a more realistic approach," Salmon says.

What drove today's decline? Probably economic data played a party, but other barely seen factors likely deserve some of the credit as well. For a rundown of noteworthy stocks, be sure to check out BloggingStocks' market wrap-up.